In today's Internet, backbone routers are capable of processing packets at 10 Gbps, creating a huge challenge for the design of network monitoring devices based on commodity hardware. To better design and thoroughly test such devices, it is crucial to test them under realistic traffic conditions. For devices located close to backbone links, this means providing traffic loads whose characteristics match, in many detailed respects, those found on real-world links at OC-48 rates and above.
Some traffic generation hardware can produce the required raw bandwidth and can also provide limited IP address variability at the flow level. Some software solutions simulate traffic at the application level but cannot produce the high bandwidth that is demanded. However, synthetic traffic generators such as these are expensive, and it is generally extremely difficult to characterize (and thus reproduce) realistic flow, packet, and address arrival patterns, or flow arrival intensities in the range of thousands per second, such as found in the Internet.
An alternative to avoid the above disadvantages is to “replay” stored real traffic. Several tools can replay captured traffic through output linecards operating at rates equal to or higher than those of the original traces. For example, stored ethernet trace data (100 Mbps-1 Gbps) may be replayed through ethernet interfaces. However, this option is not possible for very high speed links (OC-48 and above) using currently available linecards. The cards used to capture such traffic can in principle be used for retransmission. However, they are not currently designed for this more demanding purpose. These cards have very limited retransmission capabilities. Namely, they can only retransmit a trace at full link rate, completely disregarding the original packet timing. Moreover, the replay feature is not available at OC-192 speeds and above, probably due to the much higher demands that traffic generation places on the card and PC host, compared to passively capturing headers.
Accordingly, a system and method to generate realistic traffic at high speeds would be desirable. Additionally, it would be advantageous if the generated traffic provided an accurate traffic mix. Further, a highly scalable and low-cost approach to generating such traffic would be advantageous.